Attacker Value
Unknown
(0 users assessed)
Exploitability
Unknown
(0 users assessed)
User Interaction
None
Privileges Required
Low
Attack Vector
Local
0

CVE-2024-41085

Disclosure Date: July 29, 2024
Add MITRE ATT&CK tactics and techniques that apply to this CVE.

Description

In the Linux kernel, the following vulnerability has been resolved:

cxl/mem: Fix no cxl_nvd during pmem region auto-assembling

When CXL subsystem is auto-assembling a pmem region during cxl
endpoint port probing, always hit below calltrace.

BUG: kernel NULL pointer dereference, address: 0000000000000078
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) – not-present page
RIP: 0010:cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem]
Call Trace:
<TASK>
? __die+0x24/0x70
? page_fault_oops+0x82/0x160
? do_user_addr_fault+0x65/0x6b0
? exc_page_fault+0x7d/0x170
? asm_exc_page_fault+0x26/0x30
? cxl_pmem_region_probe+0x22e/0x360 [cxl_pmem]
? cxl_pmem_region_probe+0x1ac/0x360 [cxl_pmem]
cxl_bus_probe+0x1b/0x60 [cxl_core]
really_probe+0x173/0x410
? pfx_device_attach_driver+0x10/0x10
__driver_probe_device+0x80/0x170
driver_probe_device+0x1e/0x90
__device_attach_driver+0x90/0x120
bus_for_each_drv+0x84/0xe0
__device_attach+0xbc/0x1f0
bus_probe_device+0x90/0xa0
device_add+0x51c/0x710
devm_cxl_add_pmem_region+0x1b5/0x380 [cxl_core]
cxl_bus_probe+0x1b/0x60 [cxl_core]

The cxl_nvd of the memdev needs to be available during the pmem region
probe. Currently the cxl_nvd is registered after the endpoint port probe.
The endpoint probe, in the case of autoassembly of regions, can cause a
pmem region probe requiring the not yet available cxl_nvd. Adjust the
sequence so this dependency is met.

This requires adding a port parameter to cxl_find_nvdimm_bridge() that
can be used to query the ancestor root port. The endpoint port is not
yet available, but will share a common ancestor with its parent, so
start the query from there instead.

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CVSS V3 Severity and Metrics
Base Score:
5.5 Medium
Impact Score:
3.6
Exploitability Score:
1.8
Vector:
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Attack Vector (AV):
Local
Attack Complexity (AC):
Low
Privileges Required (PR):
Low
User Interaction (UI):
None
Scope (S):
Unchanged
Confidentiality (C):
None
Integrity (I):
None
Availability (A):
High

General Information

Vendors

  • linux

Products

  • linux kernel

Additional Info

Technical Analysis